Spec
I get fairly frequent Tells from Marauders who are either just rolling or new to T4 about how to spec effectively for PvP in WAR. This is a good question to have a prepared answer for, so now I've decided to write it all out so I can refer people to this blog with tips on how to spec.
First off, your spec has a lot to do with your Renown Rank, this is pretty obvious, but for a Marauder it is even stronger then it is for many other classes. A lot of classes do not need as long a rotation to kill in this game as the TTK as a Marauder is longer then any other damage class save a Magus, which is about equal. Marauders are required to purchase a lot of their Mastery abilities to get the abilities that they need.
Essentially all the abilities in the Savagery line are usful as well as the tactics with the exception now of Exhaustive Strikes (which used to be the best tactic in this game, now is useless).
Savagery is the best Mainline mastery tree for Marauders by a significant Margin. The Brutality line is only viable as a support tree or in PvE (talk about that later). Monstrosity is not without it's uses, and most Marauders should be specing into Monstro. Do not be fooled by the tooltips in Brutalities Mastery Line, while some of them look inviting they are not as effective as they lead on.
Leveling up in PvP you are going to Focus first on Savagery. Start putting points into this Mastery Tree. The First Tactic Scything Talons is an excellent Tactic, but should be taken later on, not right away. The 160 Weapon Skill and Initiative is very handy to have however you need to get to Thunderous Blows as quickly as possible. TB is probably a Marauder's best single target blow as it hits the hardest + it's Wounds Debuff. TB functions both as your opener and your finisher. Keep pumping points up until Cutting Claw, which by even looking at the tooltip will be the best Armor Debuff that Destruction has in terms of pure debuff, plus it is Undefendable. After taking CC, the next level go back and tact the ST Tactic.
Once you have Cutting Claw, TB and ST it is time to go up the Monsto tree. It will take 10 levels but put your points into the tree up until Concussive Jolt. CJ is Destruction's best Knock Down ability, 3sec and AoE arch infront of you. When you get to R40 and have Terrible Embrace you can Pull and knock your target down. Most Destro seeing this will quickly assist you and kill the target straight on. Once you have CJ you ought to have 3 points left, spec back into Savagery and take Deadly Clutch. DC will make your Tainted Claw vastly improved giving you back %25 of what your target is healed and reducing their heals by %50.
This takes you to R40, and looks like this on the wardb chart.
http://www.wardb.com/career.aspx?id=14#11:2600:0:0:9:512:25
Moving up the renown ranks all that you need to do is put points into Savagery and take Draining Swipes, an AP regeneration debuff. With your last Mastery Point at RR70 take Wave of Mutation. The Issue with WoM is that it is a good way to break Staggers. However it is also a 21s Dot, which works as an Ailment for your Healing Debuff.
http://www.wardb.com/career.aspx?id=14#13:10792:0:0:9:544:29
Aside from CJ being a solid CC Monstro scales points into Flail, which essentially is the Marauder's best “anytime” attack in terms of Damage. Corruption scales with Savagery, together this is a good combination to throw into rotation.
(You want to open always with TB. The Wounds debuff takes off the top of your targets total HP so if you do more then 1500 dmg before you apply it then you've missed out on the debuff. After that then you hit the armor debuff and heal debuff then TB will be up again. Use Corruption before you start using Flail. Keep your Armor debuff up every time the cool down is over, same with your Heal Debuff.)
At Higher Renown Ranks, with Gear in your pocket you could break off the Monstro support line and put points into Brutality, taking Growing Instability and Mutated Aggressor. These two abilities will pump your damage up but lower your Survivability. MA gives you burst, don't use it at the start of fights, use it when your target is half way dead to push it over the edge. GI is a risky tactic to use, because your burst is relative to your death. It is unreliable, however with guard and a healer it will rip people apart. I often times will go back to GI/MA support tree and run with a high wounds build so that I have more mileage.
Tactics.
Scything Talons
Brute Force
Deadly Clutch
????
The Final Tactic, has many options. I tend to use Subvert Strength or Flanking. Growing Instability if in Brutality subspec.
Morale, Most use Confusing Movements. I do sometimes, but Sever Never is better for me. I find whenever you are looking to pop CM you are already screwed. When I think about all the times I was saved by CM I probably killed 3 more with SN. M2 I use Great Fang, M3 Tzeench Reversal and M4 Frenzied Assault. In the end, saving past M2 is a waste of time. M2 is good for clusters and Morale Pushes, whenever a Morale Push is called in Vent I always go and use M2 when the enemey is at about 1/3 health and steal some kills. At RR80 your moral hits for 1224, undefendable, unmitigated.
This is the best PvP set up I have discovered in almost 2 years of playing a Marauder. It's fairly standard, I've been experimenting a lot